1. Field of Invention
The present invention relates to work lamps, and more particularly to a portable stack lamp which not only provides 360 degrees illumination but also is capable of being stacked up to increase lighting intensity.
2. Description of Related Arts
Table lamp, floor lamp, ceiling lamp, and etc. are common types of indoor lighting fixtures. Lantern lamp and spot light are outdoor lighting fixtures that generally use incandescent bulbs and halogen bulbs for illumination. Therefore, these outdoor lamps are most usually used as work lamps to provide supplemental illumination in working environments such as auto shops and factories.
Portability is the primary feature of a work lamp so that it is handy for the user to carry elsewhere for use. Therefore, both the lantern lamp and spot lamp are compact in size for easy carry from place to place. However, the user must hand carry the work lamp or hang it up near the workplace for illumination.
The luminous intensity of the conventional work lamp is limited to the power of light bulb. If a 60-watt incandescent bulb or halogen bulb is used in the lantern lamp or spot lamp, there is no way to increase or decrease the luminous intensity unless replacing the light bulb with one having a higher or lower watt.
Since reflection disc is generally mounted behind the light bulb of the convention work lamp to reflect light beam to enhance luminous intensity, either the lantern lamp or the spot lamp can only emit luminous beam in a single direction that may limit the work lamp""s application and require the user to rotate the entire work lamp by hand to direct the light beam to the area where the user wants to illuminate.
Due to the safety concern that the halogen work lamp produces great amount of heat during illumination, it not only wastes energy but also renders the halogen work lamp not being allowed to be used indoor.
It is a main object of the present invention to provide a portable stack lamp which is arranged to provide 360 degrees illumination so as to produce luminous beams in all directions. Therefore, one portable stack lamp can illuminate the surrounding that not only minimizes the number of work lamps to be used but also saves both the electrical energy and illumination cost.
It is another object of the present invention to provide a portable stack lamp which arrangement successfully equips a ring type fluorescent bulb as the light source in each lamp unit so that it can be used indoor while consuming less electrical energy than the incandescent bulb or halogen bulb of the conventional work lamp.
It is another object of the present invention to provide a portable stack lamp wherein the circular central lamp mount which is used to support the ring type fluorescent bulb therearound is used, at the same time, as a reflective ring to reflect all light beams radially outwards.
It is another object of the present invention to provide a portable stack lamp which enables the user to selectively increase or decrease its luminous intensity by simply stacking up more or less lamp unit easily anytime.
It is another object of the present invention to provide a portable stack lamp which fluorescent bulb is arranged to be easily reached and replaced, wherein the user has no need to detach all upper lamp units one by one and merely requires to unassemble the lamp unit attached on top of the lamp unit to be repaired in order to reach the fluorescent bulb therein.
It is another object of the present invention to provide a portable stack lamp which can stand on floor, support at an adjustable height and is easy to carry and roll from place to place effortlessly.
In order to accomplish the above objects, the present invention provides a portable stack lamp, comprising:
a base having a top mounting surface and a bottom supporting surface;
means for supporting the base being detachably attached to the bottom supporting surface of the base;
at least a lamp unit which comprises:
a housing which is a circular disc having a bottom wall and a surrounding wall made of transparent material;
a ring-shaped lamp mount, which is attached to a central portion of the bottom wall of the housing, having a circular outer light reflective surface and defining a receiving chamber therein and a light source chamber between the light reflective surface and the surrounding wall of the housing;
a ring type fluorescent bulb having a diameter smaller than the housing and larger than the lamp mount and a height smaller than the surrounding wall of the housing;
means for mounting the fluorescent bulb around the lamp mount inside the light source chamber of the housing;
a control circuit, which is disposed in the receiving chamber, comprising a power connector detachably connected to the fluorescent bulb, a power input terminal for electrically connecting to a power source to supply electricity to the fluorescent bulb, and a power output terminal for extended electrical connection;
a bottom attachment fastener provided at a bottom portion of the housing; and
a top attachment fastener provided at a top portion of the housing; and
a cover adapted to cover a top opening of the housing of the lamp unit;
wherein when only one lamp unit is used, the bottom attachment fastener thereof is attached to the top mounting surface of the base and the top attachment fastener is attached to the cover;
in which when two more lamp units are used, the bottom attachment fastener of the bottom layer of lamp unit is attached to the top mounting surface of the base and the bottom attachment fastener of an upper layer of lamp unit is detachably fastened to the top attachment fastener of the lower neighboring layer of lamp unit so as to stack up the lamp units in a layer on layer manner, wherein the cover is attached to the top attachment fastener of the topmost layer of lamp unit to construct the portable stack lamp of the present invention.